3M™ Wetordry™ Tri-M-ite™ Sheet 02005 is used in wet sanding, coarsest grade available for fine featheredging. Use wet or dry for sanding old finishes, fine featheredging plus surface work. It is a silicon carbide, closed coat product bonded with a waterproof resin. 280 grit. 9 inches x 11 inches.